Introduction To Si Units Worksheet (Page 5 of 6) in pdf

Introduction To Si Units Worksheet Page 5

Since 1 rem is equal to 1000 millirem, you can find that 1 sievert is equal to 1 times 10 to the 5th

millirem. 1 becquerel is equal to 1 disintegration per second.

1 curie is equal to 3.7 times 10 to the 10th disintegrations per second.

Since 1 curie is equal to 1 times 10 to the 12th picocurires, you can find that 1 times 10 to the 12th

picocurires equals 3.7 times 10 to the 10th disintegrations per second.

The unit analysis can now be completed by substituting in the conversion factors and solving the

equation.

8.63 times 10 to the negative 9th sievert per becquerel equals 3.19 times 10 to the negative 5th

millirem per picocurie.

Detector Readings

This equation is used to calculate the activity from a detector reading.

"A" represents the activity, or decay rate, measured in microcuries. This equation will be used to solve

for “A.”

To find the activity, you’ll need values for ‘G,’ ‘B,’ and efficiency.

The detector efficiency will vary based on the kind of the detector and the material being measured.

G represents the gross count, in counts per minute.

B represents the background count, also in counts per minute.

With those three values, the activity can be calculated. For example: given a detector efficiency of 10%

for Cesium-137, an average background rate of 216 counts per minute in the absence of the sample, and

a count of 25,306 counts per minute for the sample, what is the activity of the sample in microcuries?

All the values need to be substituted in.

Then it can be solved.

The activity sample is 0.11 microcuries.

Lesson Summary

Let's summarize what you have learned in this lesson:

•

The transition to measurement using SI is required by Presidential Executive Order and Public

Laws.

Introduction To Si Units Worksheet Page 5